Depositing of sand under water



A. E. BRETTING DEPOSITING OF SAND UNDER WATER Feb. 27, 1940.

s Sheets-Shae}. 1

Filed Dec. 1, 1937 vm I firmed/701? uZEBreZZa'W DEPOSITING 0F SAND UNDER WATER Filed Dec. 1, 1937 3 Sheets-Sheet 2 Feb. 27, 1940. 5 TTm 2,191,845

' DEPOSITING 0F SAND UNDER WATER Filed Dec. 1, 1931 s Sheets-Sheet s R: I, I I: W.

Patented Feb. 27, '1940 PATENT orricu DEPOSITINGAOF SAND UNDER WATER Aage Einer Bretting, Copenhagen, Denmark, as-

signor to- Christiani & Nielsen, Copenhagen, Denmark, a registered Danish firm Application December 1, 1937, Serial 'No. 177,636

In the Netherlands December 7, 1936 I 12 Claims. (01, 61- 3) The presentinvention relates to a method of depositing sand under water and carrying out the method.

' For the sake of simplicity it has been referred here and in the following specification and claims to sand only. The invention, however, is as well applicable to the use of othercohesionless materialssuch as pebble and small or larger stones or crushed stone.

'The difiiculties that have hitherto been experienced in connection with the depositing "of sand under water consist mainly in the impossiflow from the pressure pipe determines the path I bility of depositing the sand to a definite extent and in a predetermined form.

The object ofthe present invention is to obviate these diificulties, and it consists therein that a quantity of sand and water is forced through a pressure pipe with simultaneous suction through oneor several other pipes. The orifice of the suction pipe 'or'of each suctionlpi pe is so disposed in relation to the orifice of the-pressure pipe that the suction flow together with the of the sand grains issuing, from the pressure pipe. I K The accompanying drawings illustratethe method according to the invention, and a device for carrying outthe method.

Figure 1 is a diagrammatic view illustrating :a subaqueous deposit of sand in the course of being deposited and illustrating schematically a'portion .of the apparatus used. 1

Figure 2 is a vertical sectional view taken on the section line 11-11 of Figure ,1.

Figure 3 is avertical sectionaluview taken on the section line IIIIII of Figured.

Figure 4 is a vertical sectiona'l viewtaken o the section line IV-IV of Figure 1. I

Figure 5 is an elevationalv-iew illustrating the apparatus used when sand is to be introduced between a dredged river bed and a tunnel element placed in the river. i I

I Figure 6. is a diagrammatic plan .view of the device shown in Figure 5 on a smaller scale.

Figure .7 is a cross sectional View taken through .the nozzle portion of the pipes along the section nozzle.

With particular reference to Figs. 1-4. the surfaceof the water is indicated by z, and .2 indito a device for vtion is. produced in the pipes 3 cates the bed on which the sand is to be deposited. Three pipes 3, i and 5 arranged'adjacent one another, are bent horizontally underwater, and enter into a common nozzle ii. A mixture of sand'and water is forced through the central pipe 4, whereas the pipes 3 and 5 at either side thereof serve as suction pipes. In the common jects somewhat beyond the'orifices of the two suction-pipes 3 and 5.

I Through the pressure piped 'amixture of sand and" water is forced, and at the same time sucand 5. At the beginning the nozzle 6 remains stationary. The sand "contained in the jet forced through the pressure pipe settles, while water only issues from the suctionpipes 3 and 5. After a while sand will appearin water flowing through the suction pipes. .The sand concentration 'in the flow through the suction pipes will gradually increase and before long this sand. concentration will be equal to the sand contents in the mixture forced through the pressure pipe, and from now on no further deposit of sand takes place. The nozzle.

* nozzle 6 the orifice of the pressure pipe i pro- B'with the pipes 3, 4 and '5 is thereupon drawn a ,25

compact deposit of sand. The width of the deposit is dependent on'the diameter of the pipes and the velocity inthe pipes. On both sides and in front of the nozzle 6 the sand is deposited with the natural slop-e, which in Figs. 2 and 3, is indicated by the angle 8.

The illustrations in Figs. 1-4 show to scale the results that have been obtained by means of an apparatus built for experimental purposes.

Figs. 5 and dillustrate a device by means of which sand may be introduced between a dredged river bed 9 and a tunnel element it submerged in the river. The highest level of the river water is indicated by H.

The device comprises a bridge l2 travelling lengthwise on rails l3,;placedon the-roof of the submergedtunnel element. This bridge carries spouting towers it, which are arranged on the bridge I2, movable at right angle to the direction in which the latter is movable.

A vertical pipe system 55, which as .a unit can revolve about its vertical axis, and which comprises a pressure pipe it along either side of which there is placed a suction pipe I! is suspended in each of the spouting towers M. The lower part of these three pipes are all horizontally bent so as to extend into the slotted space l8 between the base of the tunnel element and the river bed.

Fig. 7 is a sectional view of the horizontal part of the pipes. On both sides of the suction pipes l1 air chambers I9 are placed providing the long, freely cantilevered pipe ends with sufficient buoyancy to enable them to maintain their horizontal position.

Furthermore the horizontal part of the pipes may be provided with rollers 20 or similar guide members (Fig. 8), serving to support and-guide the pipes along the lower surface of the structure l0.

The tunnel element illustrated in Fig. '5 is placed horizontally above the river bed. Hence, it has been referred above to vertical pipe systems l5 and horizontally bent pipe ends. Itwill, however, be understood that in case the tunnel element is inclined, as for instance *-in the case of the ramp portions, the pipe system l5 would no longer be arranged vertically,but at a right angle to the lower surface of the tunnel element. The axes on which the pipe systems rotatewill likewise alter their position as will do also the horizontal ends.

Themanner in which the sand is deposited in the space I8 is the same as that described in connection with Figs. 1-4.

The time at which the spouting towers [4 should be moved in order to obtain a progressive dense deposit of the sand is determined by means of the concentration of sand in the mixture of water and sand issuing from the suction pipes It is furthermore possibleto' give the spouting towers a slow and continuous rearward movement. As long as only water is discharged by'the suction pipes, all sand forced through the pressure pipe is deposited. When, however,'in the case of equal quantities of forced in and discharged mixture-the mixture issuing from the suction pipe has the same concentration of sand as the mixture forced through the pressure pipe, no sand will be deposited. If the spouting-towers are moved in thefirst mentioned case the displacement has taken place too early. If, however, they are not displaced until the concentration of sand is alike in the suction and in the pressure pipes as mentioned in second case, there has been an unnecessary delay. r Q

In practice the initial moving of the'tower should take place when the mixture issuing-from the suction pipes has reached a certain conoentration of sand--a concentration thatshould be maintained by moving the towers simultaneously.

The concentration of sand may be checked from the top of the spouting towers far from the inaccessible place where a deposit of sand is required. It is advisable to measure the concentration of sand in the mixtures flowing through" the suction and pressure pipes in smaller branchpipes, thus operating with smaller quantities, which facilitates the measuring.

Finally it is to be remarked that also a pressure pipe I6 and a suction pipe I I may be arranged within a common nozzle in such-a manner that the suction pipe is arranged'concentrically around the pressure pipe'(Fig. 9). Other arrangements of the orifices of the suction and pressure pipes in relation to each other are possible, either within a common nozzle or sepa- The device by means of which the method be carried out comprises according to the invention abridge traveling on or above the upper By the above invention it ispossible to control the otherwise uncontrollable movements of the sand grains, as'well as to control the extent and density of the sand deposit.

Thus a sand fill of a geometrically defined shape can be made, and this has been proved by experiments. I

According to the invention the pressure flow and thesuction fiow are preferably directed parallel or approximately parallel to the bed on to which the sand is to be deposited.

Furthermore "the depositing of the sand may according to the invention at will be performed "intermittently-or continuously at a comparatively vention will usually be carried out'in 'suchoa' manner that at the start sand will be deposited through stationary pipes, while -water only=will flow through the suction pipe or pipes. Gradually, however, only a portion of the sand issuing from the pressurepipe will be deposited, while a quantity thereof will return through the 'suction pipes. I a

When the concentration of'sand in'the stream in the'suction pipe or pipes finallybecomes equal to that in the pressure pipe, this proves that no more sand is being deposited." The'pres'surerpipe an'dthe suction pipe or pipesare then" moved backwards, whereupon a renewed deposit 'of san'd takes place, and. the concentration of sand in'th'e stream through the suction pipe orpipesfis at the same time correspondingly reduced. 2

' Through experiments made it has been proved that the sand is being deposited with-a gradient equal to the natural slope of the materiaLiatld the width of the deposit is dependenton theiZi/e locity in the pipe. V i

According to the invention there may'be employed a nozzle common for the pressure pipe and the suction pipe or pipes, which encloses the orifices of these pipes. The diameter of the-"pipes have a bearing on the width of the' san'd fill produced .i "11' 5, I

The dimensions of the deposit 'of sand-is-thus a definite function. of the velocity in the -pipe and of the diameters of thepipes. -It" isconsequently-possible to obtain a dense filling of sand also in narrow spaces in which the 'depos iting cannot be observed from the exterior. I This fact may be utilizedwith advantage in the depositing of sand beneath 'a foundation; a

tunnel element or any other submerged structure distance above the water bottom.

the underside'of which is located at a-bertain may ersa pipe system including a pressure pipe and one or several suction pipes are suspended such a manner. that the pipe system as agunity can revolve abouta vertical axis. This [pipe system extends downwards below the bottompfthe 2,191,845 structure-where n is bent'so that the orificesof the pipes' ma'y'rbe"horizontally introduced into the "space'between the said water bottom and the bed.

Finally ineasuresm'ay be taken to "provide the horizontal .part of fthe pipe system with additional. buoyancy or to arrange such guides that will secure the proper position of this part of the pipe'system in relation tothe bottom of the structure'also in case this part is of exceptional length.- v v When sand is to be deposited under water with a free surface 'and'wherethe water level is not too high in relation to the mouth of the tubes, the sand may be deposited as high as the water. level, but it will not rise above it.

In the following claims the term sand covers any cohesionless material.

I claim: v I I 1. A method of depositing sand under water which comprises subjecting a mixture of sand and water to pressure so as to direct said mixture in a direction approximately parallel to the bed on which saidsand is to be deposited and at the same timeestablishing a suction flow in a direction approximately parallel to said bed. I

' 2. A method of depositing sand under water comprising forcing a mixture; of sand and water through'an orifice subjected at the same time to the influence of a suction flow closely adjacent said orifice and then displacing said orifice in accordance with the rate at which sand is deposited.

3. A method of depositing sand under water the mixture of sand and water and the contents 'of sand in said suction, flow.

4. A device for depositng sand under water comprising a number of open ended pipes, the ends of which are positioned under water and substantially parallel to a bed on which the sand is to be deposited; means for forcing a mixture of sand and water through one of said pipes and means for exerting a suction in another of said pipes; means for displacing the pipes contin uously backward at a slow speed according to the rate at which the sand issuing from the pipe through which the mixture is being forced is deposited upon said bed. I

5.'A' device for depositing sand under water comprisinga number of open ended pipes, the ends of whichare positioned under water and substantially parallel to a bed on which the sand is to be deposited; means for forcing a mixture of sand and water through one of said pipesand means for exerting a suction in another of said pipes, means for displacing the pipes intermittently backward along small distances according to the rate at which the sand issuing from the pipe through'which the mixture is being forced is deposited upon said had.

6. A device for depositing sand under water, comprisinga number of open ended pipes the endsof which are positioned underwater and substantially parallel to a bed on which the sand is to be deposited, means for forcing a mixture of sand and water through one of said pipes and means for exerting a suctionin another of said pipes, means for displacingthe pipes backward at such a speed as may be determined by the relation between the contents of sand in the mix.-

ture issuing'fromthesuction pipe and the contents of sand in the mixture forced through the pressure pipe,

7; A device for depositing sand under water comprising a number of pipes, the orifices of which are located beneath'the water level; means for forcing a mixture of sandand water through one of saidpipes and means for exerting a suction' onanother of said pipes, the orifice of the suction pipe being so disposed in relation to the orifice of the pressure pipe that the flow in'the water caused by the suction in .the suction pipe together with the. fiow in the water caused by the pressureaction in the pressure pipe determines the path of motion of the sand grains issuing from this latter pipe, the ends of the pipe near the orificesthereof being positioned in such a Way with respect to the bed on which the sand is to be deposited that both the pressure flow and the suction flo-w are directed substantially parallel to' said bed. v

8. A device for depositing sand under Water comprising a number of pipes having their orifices located beneath thewater level, means for forcing a mixture of sand and water under pressure through one of said. pipes, means for exerting a suction on another of said pipes, so that the flow in the, water caused by the suction in the suction pipe together with the flow in the water caused by the pressure action in the pressure pipe determines the path of motion of the sandfrom said pressure pipe, and a commonnozzle enclosing the ends of said pipes.

9. A device for depositing sand under water comprising a number of pipes having their orifices, located beneath the water level, means for cated pressure pipe and the orifices of two suc tion pipes being located oneither side of said pressure pipe. 1 1

10. A device for depositing sand under water comprising a number of pipes having their orifices located beneath the-water level, means for forcing a mixture of sand and water under pressure through one of said pipes, means for exerting a suction on another of said pipes, sothat the flow in the water caused by the suction in the suction pipe together with the flow in the water caused by-the pressure action in the pressure pipe determines the path of motion of the sand from said pressure .pipe, a travelingbridge', a spouting tower on said bridge, means for revolvingsaid pipes about a substantially vertical axis, means for suspending said pipes. from said I tower and the lower ends of said pipes being bent.

11. A device for depositing sand under water the flow in the waterv caused. by the suction in the suction pipe together with the flow in the water caused by. the pressure action in the pressure pipe determines the path of motion of the sand from said pressure pipe, a traveling bridge,

-a spouting :tower: on: said bridge; means for revolving said pipes about'asubstantially vertical axis, means for suspending said pipes from said tower and the lower ends of said pipes being bent, and air boxes provided upon the bent portions of said pipes. I

12. A device for depositing sand under water comprising a number of pipes having their orifices located beneath the water-level, means for forcing a mixture of sand and water under pressure through one of said pipes, means for exerting a suction on another of said pipes,- so that thefiow inthe water cauSed by the' suction the suction pipe together with thefiow in the water caused by the pressure action in the pressure pipe determines the-path of motionof-the sand from said pressure pipe; a traveling bridge,

a spouting tower on said bridge,- means -fo-r revolving said pipes about a substantially vertical axis, means for suspending said pipes from said tower and the lower ends of said pipes being bent, and. guiding members provided upon the bent portions of said pipes. I

' AAGE EINER BRE I' NG. 

